Time switch



Feb. 24, v E EXTROM AL 1,794,067

TIME SWITCH Filed Jan. 18, 1928 2 Sheets-Sheet l KIT: Exifam.

P. J JV; Miller.

V. E. EXTROM ET AL TIME SWITCH 2 sheets-sneer,

Filed Jan. 18, 1928 Patented F eb. 24, 1931 UNITED STATES PATENT OFFICE VICTGR E. EXTROM AND PETER J. N. MILLER, OF MINNEAPOLIS, MINNESOTA.

TIME SWITCH .Application filed January 18, 1.928.

This invention relates to control means for electric circuits, particularly when such circuits are supplied to toasters and other electric cooking devices required to operate for a given time and then have the current cut of.

The invention provides an electric circuit control in the nature of a time switch and including a magnetic governor to retard the movement of the timing mechanism, said governor, in the preferred form, consisting of a disc OT metal and an electromagnet which, when energized exerts a retarding infiuence on the disc and indirectly on the i switch.

I thereoi".

For a full understanding of the invention and the merits thereof, reference is to be had to the following description and the drawings hereto attached, in which,

Figure l is a front view of an electric time switch embodying the invention.

Figure 2 is vertical sectional View oi the casing showing the enclosed parts in elevation Figure 3 is an elevational view partly in section showing the switch open.

Fignre l is a view similar to Figure 3, showing the switch close Figure is a detail sectional view on the line 55 of Figure 2.

Figure 6 is a detail sectional view on the line 66 of igure 2, looking to the left as indicated by the arrows.

Figure 7 is a fragmentary sectional view on the line 77 of Figure 3.

Corresponding and like parts are referred to in the following description and designated in the several views of the drawing by like reference characters.

The device includes a case 1 which encloses the working parts, The switch proper in- Serial No. 2%7531.

cludes spaced contacts 2 which are fixed, and a movable contact 3. The movable contact 3 is mounted upon a member 4 which consists of a bar arranged to have a limited vertical or longitudinal movement. Pins 5 or other suitable fastening means retain the member l in place, and direct it in its longitudinal movement. The pins or fastenings 5 operate in slots formed in the member 4, and engage plate of the frame 6 supporting the time mechanism. A spring 7 connected to the frame 6 normally exerts a downward pressure upon the member at to hold the switch. open. A pivoted latch 8 is provided to cooperate with the member 4 to hold the switch in closed position, as indicated most clearly in Figure 4 of the drawings. This latch has an ofi'set extension adapted to be engaged by means of a stop 9, whereby the latch is tripped and the member l released to admit of automatic opening of the switch and a breaking of the electric circuit controlled therehyc A timing mechanism controls the automatic opening or" the switch, and includes or gearing which is mounted in the f ame 6, This train of gearing includes two pr shaits l0 and 11, the shaft 10 project one end beyond the case 1, having I 7 piece 12 at the projecting end. innera denotes a power spring, one end of whici is secured to the shaft 10 and the opposite e 8 connected to the frame 6. A gear wheel is loose upon the shaft 10 and carries a p wl which coacts with the ratchet wheel 16 rast to the shaft 10 to form connecting means be tween the gear wheel 14: and the power shaft 10. A cam 16a is fast to the shaft 10 and receives the offset end 17 of the member 4. This cam 160: also receives the stop 9 which trips the latch 8 to effect disengagement thereoi from the member a to admit of automatic opening of the switch. A disc 18 is fast to the shaft 11 and preferably consists of alumi num or other metal which is amenable to magnetic influence. The numeral 19 denotes an electromagnet which is disposed with its core perpendicular to the disc 18 and close thereto to exert a retarding influence upon the disc when the electromagnet is vitalized, thereby governing the speed of the gearing and the action of the switch. A U-shaped frame 190: is connected to one end of the core and its 0pposite end is spaced from the other end of the core. The spaced ends of the core and frame constitute poles between which the disk 18 passes. A latch 20 pivoted to the'finger piece 12 is adapted to be engaged with a stop 21 to hold the switch closed for an indefinite period when required.

The numeral 23 denotes a socket member provided with contacts which are included in the electric circuit adapted to be controlled by means of the switch. A plug 24 of well known construction is adapted to cooperate with the socket 23 in a manner well understood. An electric cord connects the plug 24 with the toaster or other cooking appliance, not shown, adapted to be controlled by means of the switch. Normally the switch is in open position, as indicated most clearly in Figure 3 of the drawings. The extension 17 of the member 4 engages the low portion of the cam 16a. Rotation of the shaft 10 through a small arc effects a lifting of the member 4 and a closing of the switch by bringing the contact 3 in engagement with the contacts 2. As the shaft 10 is rotated, the spring 13 is tensioned to ef: fect movement of the timing mechanism. The shaft 10 may be rotated through a greater or less are depending upon the length of time it is desired to have the circuit remain closed. The degree of rotation of the shaft 10 may be determined by indications on the case, as

' shown most clearly in Figure 1 of the drawings.

The winding of the electromagnet 19 is preferably included in the circuit controlled by means of the switch. A slight rotation of the shaft 10 efiects a closing of the switch, and when said shaft is released from the rotating influence it is reversed by the action of the power spring 13. The speed of the timing mechanism is governed by the action of the magnet 19 upon the disc 18, and as the shaft 10 assumes a normal position the stop 9 on the cam 16a fast to said shaft trips the latch 8, thereby releasing the member 4 which is moved by the spring 7 to open the switch,

thereby breaking the circuitof the electric v time.

appliance with which the time switch is associated. When the shaft 10 is rotated a complete revolution the latch 20 may be engaged with the stop 21, thereby holding the switch in closed position for any length of The circuit may be maintained in closed position for any determinate length of time by rotating the shaft 10 through a given are which may be determined by the scale indications on the case, as herein set forth. Having thus described the invention, we claim A time switch including fized and movable circuit closing contacts, a longitudinally movable bar carrying the movable contact, means supporting, guiding and directing the bar in its movements, means yieldably holding the bar at the limit of its movement in one direction with the contacts separated, a latch adapted to hold the bar at the limit of its movement in the opposite direction with the cont-acts in engagement, a cam for moving the bar to close the circuit and in turn limited in its movement in one direction by the bar, a stop carried by the cam for tripping the latch, an operating spring tensioned by movement of the cam to close the switch, and a train of gearing actuated by the operating spring and including means for regulating the return of the cam to normal position.

In testimony whereof we afiix our signatures.

VICTOR E. EXTROM. [1 s] PETER J. N. MILLER. [L. s.] 

